A renewed probe into John Wayne Gacy, the infamous serial killer who shattered so many families four decades ago, recently helped put a California family back together.

Edyth Hutton was 24 when her younger brother, Robert, vanished in 1972. Just last year, she found herself trolling through nearly 500 profiles of unidentified bodies posted online by police from across the country.

"It was very sad and very poignant," she told ABC News.

Little things in photos, such as a belt buckle in Robert's style, made her think she could be looking at her brother's body. In all, she found six profiles she felt "were really likely," submitting contact information for each.

"I only heard back from one of them. And that was Jason Moran," she said, referring to a detective from the Cook County Sheriff's Office outside Chicago.

Moran's office reopened the Gacy case two years ago, hoping to identify the last of eight unidentified victims. And Moran, a 15-year veteran of the force, became the one-man Gacy squad.

Edyth Hutton's tip became Lead #68.

Her brother had disappeared during Gacy's reign of terror near Chicago, and Robert Hutton was the quintessential Gacy victim: young, white, a bit of a vagabond often looking for work at places like the construction company Gacy owned.

Last Edyth Hutton heard, her brother was shuffling his way from the East Coast toward California, potentially placing him in the Chicago area at the time.

By all accounts, the two had been close growing up and playing together in Lancaster, Calif., a small, desert town about 70 miles north of Los Angeles.

Courtesy Edyth Hutton

PHOTO: Robert Hutton and his older sister Edyth Hutton.

After high school, Robert Hutton excitedly joined his sister, her new husband and their new baby on a road-trip across the country, living out of a pick-up truck and finding flashes of work along the way. But when the group landed in Colorado, Robert Hutton decided to stay there.

That was 42 years ago, and the last time Edyth Hutton saw her brother.

In the years afterward, her mother "tried hard to find him," poring over old phone bills showing where his past collect-calls originated, and urging local authorities in those areas to help, according to Edyth Hutton.

"She followed the trail as far as she could" and "just came to the conclusion that he was dead," Edyth Hutton said. "It was a sadness that she carried to her grave" in 1989.

Edyth Hutton carried on the effort, taking advantage of the Internet boom in the late 1990s.

She collected the names and addresses of every "Robert," "Robbie" or "Bob Hutton" she could find, sending handmade postcards to nearly 400 of them across the country.

The postcards concluded: "If this is not you, please forgive the intrusion and disregard this card."

That's what all of the recipients did, and another decade of fruitless online searches followed.

So when, in October 2011, Cook County Sheriff Tom Dart announced his office was looking for leads in a new effort to identify eight of Gacy's 33 victims, Edyth Hutton thought she may have figured out her brother's fate. She contacted the sheriff's office.

But when Moran, the detective, did a little digging, he determined her brother was anything but dead, recently living in Breckenridge, Colo., and then moving to an unknown place.

For Moran, one thing was clear: Lead #68 was not a Gacy victim.

Moran, though, said he felt compelled "to follow through," especially after hearing that Robert Hutton's father, living in Washington, had survived a desperate battle with cancer.

"I've been meeting with these families of missing persons, and … even after 30 or 40 years -- they just have this sadness about them, like, 'Where is my missing child?'" Moran told ABC News.

So earlier this year, determined to find Robert Hutton, Moran decided to run the name through online records once more.

This time, a Robert Hutton and an address popped up in Stevensville, Mont., a tiny town with "beautiful views, outdoor recreation and watchable wildlife," as a state website describes it.

In April, at Moran's request, an officer from the Ravalli County Sheriff's Office was dispatched to the address. Within minutes of arriving, the officer put Moran on the phone with the man he'd been trying to find.

"[Moran] goes, 'Well, I guess you're not dead,'" Hutton recalled. "I go, 'No, not the last time I checked.'"

Moran remembers Hutton saying to him, "They want to know about me still? After all this time, after 41 years?" To which Moran responded: "Yes, they do, and they think that you were killed by a serial killer.'"

At the end of the call that day in April, Moran asked Hutton if he objected to his sister now having his phone number.

"I said, 'Hell no,' and that was the start of it," Hutton recalled.

Then it was Edyth Hutton's turn to learn the good news.

"I got a call from [Moran], and he said, 'Edyth, are you sitting down?'" Edyth Hutton recalled, joyfully laughing while retelling the story recently. "And my heart was pounding. I said, 'Yes, I am. Do you have some info for me?' He said, 'I do.' And very quickly he said, 'I found your brother and he's alive and well.' And [it] was just like a hole that I had not known the size of in my heart was filled. … It was fabulous news. I was crying and laughing at the same time."

The next day, in what she dubbed "a miracle," Edyth Hutton heard her brother's voice for the first time in so long.

She began her telephone call to him: "Hi bro, this is your sister."

"I emphasized to him that we had never stopped looking for him, and still loved him, and that we're here if he wanted us," Edyth Hutton recalled.

When asked by ABC News how he disappeared for so long, Robert Hutton responded, "Just neglect."

Hutton said he spent a number of years exploring and caving throughout the Southwest, leaving him with no fixed address and little opportunity to stay connected with others.

"And, you know, procrastination is my middle name," he said. "It just kind of happened that we got out of touch, and then when we tried to get in touch we had no contact [information]."

By the early 1980s, Robert Hutton settled into a life near Breckenridge, Colo., starting his own construction and carpentry business there. Though he had some serious relationships, he never married.

He recently said he would think about his family "fondly," and he tried "a little bit" in the 1990s to see if he could find them.

Then, in the wake of the 2008 financial meltdown, work in Colorado "just tanked," wages plummeted, and he basically went bankrupt. Plus, "a lot of my friends moved, and there was no real draw to keep me there," Hutton said.

So in 2011 he moved to Montana, where some of his friends were living. For work, he helped build horse barns and remodeled some buildings. Now, at 62, he's working in an ammunition factory and living in a trailer he bought for himself.

He's also talking to his sister and father each week, often for as long as an hour at a time.

It's like "old buddies, old friends" chatting, Robert Hutton said of conversations with his sister.

Their aging father, now 87, and new step-mother have already driven twice to see Robert Hutton in Montana.

"It was great," Robert Hutton said of his father's first visit in July, adding, "I told him, 'Well, now I know why I'm so ugly.'" They shared a laugh over that.

In a thank-you letter to Moran after the visit, Robert Hutton's father called the reunion "very emotional for both of us."

Sister and brother, however, haven't been able to visit each other yet, hindered by financial limitations on both sides and the long hours Robert Hutton puts in at the factory.

"We will see each other as soon as we can. We know that," said Edyth Hutton, now living in Lake Tahoe, Nev.

The reunion will be thanks to the work of detective Moran, who went "the extra mile to bring something good out of a tragedy like [the] John Wayne Gacy episode," said Robert Hutton.

In fact, since Moran's office reopened the case in 2011 – 17 years after Gacy was executed – four other missing men have been found alive and reunited with their families. One of the unknown Gacy victims has also been identified.

And this Christmas, for the first time in four decades, the Hutton family will be able to share the holiday together – even if miles apart.

"I already got the cookies figured out that I'm going to bake and send them," Robert Hutton said.